How Daylight Saving Time Affects Your Health

It's that time of year again. Don't let the time change get your body off track.

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Daylight saving time is set to end this Sunday, November 1, at 2 a.m.—so don’t forget to set your clocks back an hour and adjust the brew time on your coffeemaker. But while it might seem like the hour is no big deal, the reality is that the beginning and end of daylight saving time twice a year can have a real impact on our health.



“This, of course, is the good time of year—we gain an hour,” says Phillip Gehrman, Ph.D., assistant professor of psychiatry at the University of Pennsylvania. “It’s much better than the other side of DST.” Indeed, gaining an hour of sleep sounds like an early Christmas present to 35 percent of Americans who report less than seven hours of sleep per night.

When we “spring back” in March, we lose an hour of sleep. Sleep deprivation can do more than make you feel sluggish—you may find yourself craving high-carb or high-fat food late at night (also known as “the munchies”) or making unhealthy purchases the following day. Sleep deprived students perform poorly in school, and lack of sleep might cause a host of problems for your brain, including a loss of brain tissue.

While there’s no denying that the extra hour of sleep this weekend has the potential to boost your energy and your mood, though, your body will probably adjust quickly to the time difference. Gehrman compares it to a mild jetlag, but one that only takes 24 hours to overcome.

Even though your body will probably regulate fairly quickly to the hour-long difference, the real difference in sleep in the cooler months has more to do with shift in daylight that comes after the time change, rather than the time change itself.

“Sleep changes in the winter,” explains Gehrman. “For some people, it might manifest as insomnia, but oftentimes, it’s this extra sleepiness. You don’t feel as alert during the day.”

The reason, according to sleep experts, is lack of light. For some, this can translate into seasonal affective disorder (SAD), which is often marked by signs of depression. For others, the early sunsets just trigger a premature desire to crawl into bed.

“As we start losing sunlight, our body starts to produce melatonin,” explains Winter, referring to the brain chemical responsible for making us tired. “As the sky starts to darken, that’s the trigger for release of melatonin.” In response to this feeling of sluggishness, you may be less likely to hit the gym or cook a big dinner after work.

And even though we’re far more excited to fall back than spring forward, sleep specialist and neurologist Dr. Chris Winter says that losing an hour in the spring may be better for our bodies.

To combat these hibernating tendencies, both Gerhman and Winter suggest sticking to a sleep routine—this means no three-hour naps in the middle of the day, and trying to wake up at the same time every morning. This includes weekends—according to Gehrman, its best to keep your weekday and weekend schedules almost identical. Sleeping in until noon might sound appealing, but your body won’t react well to such a drastically different sleep cycle.

If you’re the type that is especially affected by time change and the sudden loss of daylight, look for ways to get natural light throughout the workday, says Winter. Whether it means eating in a well-lit break room for lunch, or taking a midday walk outside, the light will impact your mood and help you stay on schedule. If you can’t find a way to work natural light into your day, opt for a “happy lamp” for a similar effect.

“If you’re sleepy at night, but it’s not time to go to bed, expose yourself to a more brightly lit environment,” Winter suggests. “If you’re struggling to fall asleep, make sure to avoid bright lights in the evenings. Keep them dim and soft.”